U.S. patent number 11,343,019 [Application Number 16/640,548] was granted by the patent office on 2022-05-24 for communication apparatus and method.
This patent grant is currently assigned to SONY CORPORATION. The grantee listed for this patent is SONY CORPORATION. Invention is credited to Shigeru Sugaya, Yusuke Tanaka.
United States Patent |
11,343,019 |
Tanaka , et al. |
May 24, 2022 |
Communication apparatus and method
Abstract
Provided is a communication apparatus and a method that allow
for synthesis of information using an original signal and a
retransmission signal for retransmitting information of the
original signal whose demodulation has failed, in wireless
communication with independent physical layer and MAC layer.
Information is transmitted regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed to a sender of the
retransmission signal, and the retransmission signal transmitted
from the sender is received on the basis of the information
regarding the configuration of the retransmission signal
transmitted. The present disclosure is applicable, for example, to
a transmission/reception apparatus, a communication apparatus, an
information processing apparatus, electronic equipment, a computer,
a storage medium, and a system, and so on.
Inventors: |
Tanaka; Yusuke (Tokyo,
JP), Sugaya; Shigeru (Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
N/A |
JP |
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|
Assignee: |
SONY CORPORATION (Tokyo,
JP)
|
Family
ID: |
1000006328034 |
Appl.
No.: |
16/640,548 |
Filed: |
August 17, 2018 |
PCT
Filed: |
August 17, 2018 |
PCT No.: |
PCT/JP2018/030488 |
371(c)(1),(2),(4) Date: |
February 20, 2020 |
PCT
Pub. No.: |
WO2019/044535 |
PCT
Pub. Date: |
March 07, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200252163 A1 |
Aug 6, 2020 |
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Foreign Application Priority Data
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Aug 31, 2017 [JP] |
|
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JP2017-166870 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
84/12 (20130101); H04L 1/1896 (20130101); H04L
1/08 (20130101); H04L 1/1664 (20130101) |
Current International
Class: |
H04L
1/08 (20060101); H04L 1/18 (20060101); H04W
84/12 (20090101); H04L 1/16 (20060101) |
Field of
Search: |
;370/328 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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Sep 2015 |
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WO |
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2019/021588 |
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Jan 2019 |
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WO |
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Other References
Qiao, et al., "BlockAck Bitmap", IEEE 802.11-16/0404r0, Mar. 12,
2016, 25 pages. cited by applicant .
Office Action for AU Patent Application No. 2018326862, dated May
21, 2021, 5 pages of Office Action. cited by applicant .
Qiao, et al., "BlockAck Bitmap", IEEE 802.11-16/0404r0, Mar. 12,
2016, 24 pages. cited by applicant .
International Search Report and Written Opinion of PCT Application
No. PCT/JP2018/030488, dated Oct. 30, 2018, 12 pages of ISRWO.
cited by applicant .
Extended European Search Report of EP Application No. 18851426.9,
dated Aug. 6, 2020, 09 pages. cited by applicant.
|
Primary Examiner: Solinsky; Peter G
Assistant Examiner: Dewan; Sanjay K
Attorney, Agent or Firm: Chip Law Group
Claims
The invention claimed is:
1. A communication apparatus, comprising: circuit configured to:
transmit first information to a sender of a retransmission signal,
wherein the first information is regarding a configuration of the
retransmission signal, and the retransmission signal includes
second information of an original signal whose demodulation has
failed; and receive the retransmission signal transmitted from the
sender, wherein the first information includes: a first identifier
of a first piece of a plurality of pieces of retransmission data of
the second information, and a second identifier of a second piece,
succeeding the first piece, of the plurality of pieces of the
retransmission data, and the second identifier is in a bitmap
format relative to the first identifier as a reference.
2. The communication apparatus of claim 1, wherein the first
information further includes third information regarding an
identifier of an MPDU (MAC Protocol Data Unit) and fourth
information regarding a length of the MPDU.
3. The communication apparatus of claim 1, wherein the first
information further includes information regarding a setting, and a
signal is synthesized using the original signal and the
retransmission signal, based on the setting.
4. The communication apparatus of claim 1, wherein the circuit is
further configured to transmit the first information as part of a
transmission request frame for the retransmission signal.
5. The communication apparatus of claim 1, wherein the circuit is
further configured to exchange capability information with the
sender of the retransmission signal, and a signal is synthesized
using the second information of the original signal and third
information of the retransmission signal, based on the capability
information.
6. The communication apparatus of claim 1, wherein the circuit is
further configured to negotiate an MPDU (MAC Protocol Data Unit)
unit size in a MAC (Media Access Control) layer with the sender of
the retransmission signal.
7. The communication apparatus of claim 1, wherein the circuit is
further configured to: retain bit strings acquired by demodulation
of the original signal; and synthesis a signal using the original
signal and the retransmission signal, by using the retained bit
strings and bit strings acquired by demodulation of the
retransmission signal received based on the first information.
8. The communication apparatus of claim 1, wherein the circuit is
further configured to: retain the original signal; and perform
information synthesis using the retained original signal and the
retransmission signal received based on the first information
signal at an intermediate stage of processing until conversion of a
signal received by the circuit into data.
9. A communication method, comprising: by a communication
apparatus: transmitting first information to a sender of a
retransmission signal, wherein the first information is regarding a
configuration of the retransmission signal, and the retransmission
signal includes second information of an original signal whose
demodulation has failed; and receiving the retransmission signal
transmitted from the sender, wherein the first information
includes: a first identifier of a first piece of a plurality of
pieces of retransmission data of the second information, and a
second identifier of a second piece, succeeding the first piece, of
the plurality of pieces of the retransmission data, and the second
identifier is in a bitmap format relative to the first identifier
as a reference.
10. A communication apparatus, comprising: a circuit configured to:
receive first information regarding a configuration of a
retransmission signal, wherein the retransmission signal includes
second information of an original signal whose demodulation has
failed, generate the retransmission signal; and transmit the
generated retransmission signal to a sender of the first
information regarding the configuration of the retransmission
signal, wherein the first information includes: a first identifier
of a first piece of a plurality of pieces of retransmission data of
the second information, and a second identifier of a second piece,
succeeding the first piece, of the plurality of pieces of the
retransmission data, and the second identifier is in a bitmap
format relative to the first identifier as a reference.
11. The communication apparatus of claim 10, wherein the first
information further includes third information regarding an
identifier of an MPDU (MAC Protocol Data Unit) and fourth
information regarding a length of the MPDU.
12. The communication apparatus of claim 10, wherein the first
information further includes information regarding a setting of
information synthesis using the original signal and the
retransmission signal.
13. The communication apparatus of claim 10, wherein the circuit is
further configured to receive the first information regarding the
configuration of the retransmission signal as part of a
transmission request frame of the retransmission signal.
14. The communication apparatus of claim 10, wherein the circuit is
further configured to exchange capability information with the
sender of the first information, and the capability information is
regarding information synthesis using the second information of the
original signal and third information of the retransmission
signal.
15. The communication apparatus of claim 10, wherein the circuit is
further configured to negotiate an MPDU (MAC Protocol Data Unit)
unit size in a MAC (Media Access Control) layer with the sender of
the first information regarding the configuration of the
retransmission signal.
16. The communication apparatus of claim 10, wherein in a case
where retransmission of data that has already been discarded is
requested, the circuit is further configured to notify a requester
that the data has already been discarded.
17. The communication apparatus of claim 16, wherein the circuit is
further configured to notify the requester that the retransmission
data has already been discarded based on transmission of specific
data to the requester.
18. A communication method, comprising: by a communication
apparatus: receiving first information regarding a configuration of
a retransmission signal, wherein the retransmission signal includes
second information of an original signal whose demodulation has
failed; generating the retransmission signal; and transmitting the
generated retransmission signal to a sender of the first
information regarding the configuration of the retransmission
signal, wherein the first information includes: a first identifier
of a first piece of a plurality of pieces of retransmission data of
the second information, and a second identifier of a second piece,
succeeding the first piece, of the plurality of pieces of the
retransmission data, and the second identifier is in a bitmap
format relative to the first identifier as a reference.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a U.S. National Phase of International Patent
Application No. PCT/JP2018/030488 filed on Aug. 17, 2018, which
claims priority benefit of Japanese Patent Application No. JP
2017-166870 filed in the Japan Patent Office on Aug. 31, 2017. Each
of the above-referenced applications is hereby incorporated herein
by reference in its entirety.
TECHNICAL FIELD
The present technology relates to a communication apparatus and a
method and relates particularly to a communication apparatus and a
method that allow for synthesis of information using an original
signal and a retransmission signal for retransmitting information
of the original signal whose demodulation has failed, in wireless
communication with independent physical layer and MAC layer.
BACKGROUND ART
A technique called HARQ (Hybrid Automatic Repeat-request) has been
available so far that provides, in wireless communication, a gain
over normal retransmission by properly synthesizing information
regarding a signal whose demodulation has failed and information
regarding a signal received by retransmission.
Incidentally, in a wireless LAN (Local Area Network), a physical
layer and a transport layer are independent of each other. The
physical layer handles modulation and demodulation processes and
coding and decoding processes on received signals. The transport
layer includes a MAC layer that identifies details and an order of
signals. Because of a variable frame length, in the case where
block coding is used, a coding unit thereof is independent of the
frame length in the MAC layer. This has made it difficult to apply
HARQ.
For this reason, a method was conceived that permits identification
of signals to be synthesized and application of HARQ to the
wireless LAN by adding an HARQ header including an identifier and a
length of a frame to a physical layer header (refer, for example,
to PTL 1).
CITATION LIST
Patent Literature
[PTL 1]
Japanese Patent No. 5254369
SUMMARY
Technical Problem
However, in the case of the method described in this PTL 1, a
significant increase in overhead or an increase in buffer usage may
occur, thus making it difficult to realize the application of
HARQ.
The present disclosure has been devised in light of the foregoing,
and it is an object of the present disclosure to allow for
synthesis of information using an original signal and a
retransmission signal for retransmitting information of the
original signal whose demodulation has failed, in wireless
communication with independent physical layer and MAC layer.
Solution to Problem
A communication apparatus of an aspect of the present technology is
a communication apparatus that includes a communication section
adapted to transmit information regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed to a sender of the
retransmission signal and receive the retransmission signal
transmitted from the sender on the basis of the information
regarding the configuration of the retransmission signal
transmitted.
A communication method of an aspect of the present technology is a
communication method including, by a communication apparatus,
transmitting information regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed to a sender of the
retransmission signal, and receiving the retransmission signal
transmitted from the sender on the basis of the information
regarding the configuration of the retransmission signal
transmitted.
A communication apparatus of another aspect of the present
technology is a communication apparatus that includes a
communication section adapted to receive information regarding a
configuration of a retransmission signal for retransmitting
information of an original signal whose demodulation has failed,
generate the retransmission signal on the basis of the information
regarding the configuration of the retransmission signal received,
and transmit the generated retransmission signal to a sender of the
information regarding the configuration of the retransmission
signal.
A communication method of another aspect of the present technology
is a communication method including, by a communication apparatus,
receiving information regarding a configuration of a retransmission
signal for retransmitting information of an original signal whose
demodulation has failed, generating the retransmission signal on
the basis of the information regarding the configuration of the
retransmission signal received, and transmitting the generated
retransmission signal to a sender of the information regarding the
configuration of the retransmission signal.
In the communication apparatus and the method of an aspect of the
present technology, information regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed is transmitted to a sender of
the retransmission signal, and the retransmission signal
transmitted from the sender is received on the basis of the
information regarding the configuration of the retransmission
signal transmitted.
In the communication apparatus and the method of another aspect of
the present technology, information regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed is received, the
retransmission signal is generated on the basis of the information
regarding the configuration of the retransmission signal received,
and the generated retransmission signal is transmitted to a sender
of the information regarding the configuration of the
retransmission signal.
Advantageous Effects of Invention
The present technology allows for communication. Also, the present
technology allows for synthesis of information using an original
signal and a retransmission signal for retransmitting information
of an original signal whose demodulation has failed, in wireless
communication with independent physical layer and MAC layer.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a diagram illustrating a main configuration example of a
communication system.
FIG. 2 is a diagram illustrating a main configuration example of a
communication apparatus.
FIG. 3 is a diagram illustrating a main configuration example of a
modulation/demodulation section.
FIG. 4 is a diagram describing an example of a communication
sequence.
FIG. 5 is a diagram illustrating an example of a frame format by
which HARQ information is notified.
FIG. 6 is a diagram illustrating an example of a frame format by
which HARQ information is notified.
FIG. 7 is a diagram illustrating a configuration example of a Poll
frame.
FIG. 8 is a flowchart describing an example of a flow of a
retransmission data transmission process.
FIG. 9 is a flowchart describing an example of a flow of a
retransmission data reception process.
FIG. 10 is a diagram describing an example of a communication
sequence.
FIG. 11 is a diagram describing an example of a communication
sequence.
FIGS. 12A and 12B depict diagrams illustrating a configuration
example of a Trigger frame.
FIG. 13 is a block diagram illustrating a main configuration
example of a computer.
DESCRIPTION OF EMBODIMENT
A description will be given below of a mode for carrying out the
present disclosure (hereinafter referred to as an embodiment). It
should be noted that the description will be given in the following
order.
1. First embodiment (communication system)
2. Others
1. First Embodiment
<HARQ>
Recent years have witnessed a number of terminals engaging in
communication in the same space and at the same frequency thanks to
widespread use of wireless terminals. In such a dense environment,
an SINR (Signal to Interference plus Noise power Ratio) changes
dynamically on the receiving side due to collision between
transmission signals or other causes, resulting in an increasing
number of signals that cannot be demodulated properly. In the case
where a signal cannot be demodulated properly, it is common to
request retransmission of the signal and perform reception once
again, thus ensuring communication quality. However, if
retransmission is repeated a number of times, the retransmission
itself consumes communication resources, possibly deteriorating the
system's communication quality as a whole.
For this reason, a technique called HARQ (Hybrid Automatic
Repeat-request) was conceived to realize efficient retransmission.
HARQ is a technique that synthesizes information using an original
signal and a retransmission signal for retransmitting information
of the original signal whose demodulation has failed. Proper
synthesis of information of the original signal and information of
the retransmission signal by using this HARQ presumably contributes
to reduced resource consumption attributable to retransmission as
compared to normal retransmission (ARQ (Automatic Repeat-request)),
thus ensuring the system's communication quality as a whole.
Incidentally, for example, in the case of a wireless LAN (Local
Area Network), a physical layer and a transport layer are
independent of each other. The physical layer handles modulation
and demodulation processes and coding and decoding processes on
received signals. The transport layer includes a Media Access
Control (MAC) layer that identifies details and an order of
signals. Also, because of a variable frame length, in the case
where block coding is used, a coding unit thereof is independent of
the frame length in the MAC layer. In other words, in the case
where an error occurs in a certain frame in the MAC layer, one
cannot tell in which coding block the error has occurred, making it
difficult to distinguish correctly received bit strings and use
those strings for synthesis. Also, if a signal is at an
intermediate stage of processing between its reception and its
conversion into bit strings, it is impossible to identify which
frame's information is included in the signal, thus making it
difficult to synthesize the original signal and the retransmission
signal in a linked way at the intermediate stage of processing. For
this reason, it has been difficult to simply apply HARQ to the
wireless LAN communication.
In PTL 1, the identification of signals to be synthesized and the
application of HARQ to the wireless LAN are made possible by adding
an HARQ header including an identifier and a length of a frame to a
physical layer header.
In a normal case, however, a physical layer header includes
important information in terms of communication. Therefore, highly
reliable modulation is used. For this reason, storing information
regarding a large number of frame identifiers and lengths in a
physical layer header has entailed a potential risk of a
significant increase in overhead. Also, the communication apparatus
on the receiving side cannot tell when HARQ-based retransmission
takes place, making it necessary for the communication apparatus on
the receiving side to be on standby constantly for reception
operation compliant with HARQ and, therefore, have a number of
buffers to continuously retain the signal. Also, in the case where
the communication apparatus on the transmitting side discards a
frame, the communication apparatus on the receiving side cannot
detect the discard. As a result, the communication apparatus on the
receiving side unnecessarily retains the signal in the buffer,
possibly resulting in wasteful buffer consumption. For this reason,
it has been difficult to realize HARQ in the wireless LAN by using
this method.
<Transmitting HARQinfo>
As such, HARQ is realized in the wireless LAN without requiring any
additional information in the physical layer header. More
specifically, for example, the communication apparatus on the
receiving side of HARQ-based retransmission explicitly notifies the
transmitting side of a data transmission request together with HARQ
information such as an identifier, an order, and a length, of data,
and the communication apparatus on the transmitting side identifies
data to be transmitted on the basis of HARQ information, decides
the order and modulation and coding schemes, and transmits a normal
signal that does not include any additional information, in
response to the request.
The communication apparatus on the receiving side already retains
the identifier, the order, the length, and so on, of the data,
included in the signal. Therefore, doing so allows to identify in
which coding block an error has occurred in the MAC layer, thus
making it possible to distinguish bit strings that have been
properly received and use such bit strings for synthesis. Also, it
becomes possible to synthesize an original signal and a
retransmission signal in a linked way at an intermediate stage of
processing between reception and conversion into bit strings.
<Communication System>
FIG. 1 is a block diagram illustrating a main configuration example
of an embodiment of a communication system to which the present
technology is applied. A communication system 100 illustrated in
FIG. 1 is a system that forms what is generally called a wireless
LAN and has a base station 101 (AP1), a terminal apparatus 102-1
(STA1), and a terminal apparatus 102-2 (STA2).
The base station 101 (AP1) is a communication apparatus that is
also referred to as an access point and functions as what is
generally called a parent unit and wirelessly communicates with the
terminal apparatus 102-1 (STA1) and the terminal apparatus 102-2
(STA2), which are what are generally called child units. This
wireless communication may be carried out through any scheme as
long as the physical layer and the MAC layer are independent of
each other. For example, a wireless communication scheme
standardized in IEEE (Institute of Electrical and Electronic
Engineers) 802.11 may be used.
In the description given below, in the case where there is no need
to distinguish between the terminal apparatus 102-1 and the
terminal apparatus 102-2 for description, these apparatuses will be
referred to as terminal apparatuses 102. It should be noted that
the configuration illustrated in FIG. 1 is merely an example and
that the configuration of the communication system 100 is arbitrary
and not limited to this example. For example, the number of base
stations 101 and that of terminal apparatuses 102 are arbitrary,
respectively, and not limited to the example illustrated in FIG. 1.
Also, a connection relationship between the apparatuses is also
arbitrary.
HARQ is applied to the communication system 100 configured as
described above. In other words, in the case where demodulation of
a received signal (also referred to as an original signal) fails,
the base station 101 and the terminal apparatus 102 synthesize
information by using HARQ. In other words, the base station 101 and
the terminal apparatus 102 cause information lost as a result of
failure of the demodulation of the original signal thereof to be
retransmitted as a retransmission signal and properly synthesize
information of the original signal (also referred to as original
information) and information of the retransmission signal (also
referred to as retransmission information) by using the original
signal and the retransmission signal.
At this time, the base station 101 and the terminal apparatus 102
on the signal retransmission requesting side carry out HARQ to
which the present technology is applied. In other words, the base
station 101 and the terminal apparatus 102 transmit, in addition to
a retransmission request, information regarding the configuration
of the retransmission signal to a sender of the retransmission
signal, thus causing the sender to transmit the retransmission
signal based on the information regarding the configuration of the
retransmission signal.
<Communication Apparatus>
FIG. 2 is a block diagram illustrating a main configuration example
of an embodiment of a communication apparatus to which the present
technology is applied. The base station 101 and the terminal
apparatus 102 illustrated in FIG. 1 have a configuration similar to
that of a communication apparatus 200 illustrated in FIG. 2 as a
configuration related to wireless communication. In other words,
the communication apparatus 200 can be used as the base station 101
and the terminal apparatus 102 in the communication system 100
illustrated in FIG. 100. In the description given below, the
communication apparatus 200 illustrated in FIG. 2 will be used to
describe the main configurations of the base station 101 and the
terminal apparatus 102 illustrated in FIG. 1.
The communication apparatus 200 illustrated in FIG. 2 wirelessly
communicates with another communication apparatus through a
wireless communication scheme standardized in IEEE802.11. Also, the
communication apparatus 200 has an HARQ function, thus making the
communication apparatus 200 capable of handling retransmission of
information through HARQ on its own, causing a communication
counterpart to handle retransmission, or handling both tasks.
Also, in the case where it is possible to cause the communication
counterpart to retransmit information through HARQ, the
communication apparatus 200 can carry out, through the HARQ,
information synthesis by using the original signal and the
retransmission signal thereof (i.e., properly synthesize original
information and retransmission information). This synthesis of
information through the HARQ (synthesis of information by using the
original signal and the retransmission signal) may be carried out
as data acquired by the demodulation of a signal or at an
intermediate stage of processing before conversion into data (bit
strings) (e.g., as an I signal and a Q signal).
In other words, the communication apparatus 200 may either properly
synthesize original data acquired by the demodulation of the
original signal and retransmission data acquired by the
demodulation of the retransmission signal or properly synthesize
the original signal and the retransmission signal at an
intermediate stage of processing. Needless to say, the
communication apparatus 200 may be capable of performing both tasks
(capable of synthesizing in either way).
It should be noted that which specific method to be used for
information synthesis through this HARQ is arbitrary. For example,
a lost portion of the original information may be replaced with the
retransmission information. Alternatively, for example, the
original signal may be used for demodulation of the retransmission
signal.
As illustrated in FIG. 2, the communication apparatus 200 includes
a control section 201, a data processing section 202, and a
wireless communication section 203. The wireless communication
section 203 includes a modulation/demodulation section 211, a
signal processing section 212, a channel estimation section 213, a
wireless interface section 214-1, an amplifier section 215-1, an
antenna 216-1, a wireless interface section 214-2, an amplifier
section 215-2, and an antenna 216-2. Further, the communication
apparatus 200 includes a power supply section 221.
It should be noted that in the case where there is no need to
distinguish between the wireless interface section 214-1 and the
wireless interface section 214-2 for description, these components
will be referred to as wireless interface sections 214. Also, in
the case where there is no need to distinguish between the
amplifier section 215-1 and the amplifier section 215-2 for
description, these components will be referred to as amplifier
sections 215. Further, in the case where there is no need to
distinguish between the antenna 216-1 and the antenna 216-2 for
description, these components will be referred to as antennas
216.
Although two wireless interface sections 214, two amplifier
sections 215, and two antennas 216 each are depicted in FIG. 2,
these numbers are arbitrary, and there may be only one each of
these components. Alternatively, there may be three or more each of
these components.
Also, the wireless interface section 214, the amplifier section
215, and the antenna 216 may be combined into a single component
(may be configured as a single processing section). Also, the
wireless interface section 214 may have the function of the
amplifier section 215 so that the amplifier section 215 is
omitted.
In the case where data input from an upper layer is transmitted,
the data processing section 202 generates a packet for wireless
transmission from the data and performs processes such as addition
of a header for media access control (MAC (Media Access Control))
and addition of an error detection code. The data processing
section 202 provides the processed data to the
modulation/demodulation section 211.
In the case where received data is supplied from the
modulation/demodulation section 211, the data processing section
202 analyzes the MAC header, detects packet errors, performs a
reorder process, and handles other tasks. Also, the data processing
section 202 synthesizes information on the basis of HARQ
information. For example, the data processing section 202 properly
synthesizes the original data acquired by the demodulation of the
original signal and the retransmission data acquired by the
demodulation of the retransmission signal. The data processing
section 202 provides the processed data to its upper protocol
layer.
The control section 201 handles passing of information between
different sections. Also, the control section 201 sets parameters
for the modulation/demodulation section 211 and the signal
processing section 212, schedules packets in the data processing
section 202, and handles other tasks. Further, the control section
201 sets parameters for each of the wireless interface sections 214
and each of the amplifier sections 215, controls transmission
power, and handles other tasks.
Also, the control section 201 performs processes such as retaining
capability information of the communication apparatus 200, finding
out about capability information of the communication counterpart,
retaining a negotiation result on MPDU size information, making
determination as to whether or not to negotiate the size, making
determination as to whether or not to request retransmission,
generating HARQ information, making determination as to whether or
not a retransmission request has been received, generating
retransmission information, retaining information required for
retransmission of a signal using HARQ such as HARQ information, and
generating retransmission information on the basis of HARQ
information.
Further, the control section 201 controls the data processing
section 202 and each of the processing sections (the
modulation/demodulation section 211 to the antennas 216) of the
wireless communication section 203, causing these sections to
perform processes such as exchanging capability information,
negotiating an MPDU size, transmitting and receiving an original
signal, acquiring original data, detecting errors (making
determination as to whether reception has succeeded or failed),
retaining the original signal (original data), transmitting and
receiving BA, transmitting and receiving a retransmission request
signal including HARQ information, transmitting and receiving a
retransmission signal, and synthesizing information by using an
original signal and a retransmission signal through HARQ.
The wireless communication section 203 performs processes regarding
wireless communication such as transmitting and receiving
signals.
In the case of signal transmission, the modulation/demodulation
section 211 performs encoding, interleaving, modulation, and other
processes on the basis of coding and modulation schemes set by the
control section 201 for data input from the data processing section
202, thus generating a data symbol stream. The
modulation/demodulation section 211 supplies the data symbol stream
to the signal processing section 212.
In the case of signal reception, the modulation/demodulation
section 211 performs, on input from the signal processing section
212, processes opposite to processes at the time of signal
transmission described above. For example, the
modulation/demodulation section 211 performs demodulation,
decoding, and other processes on the signal supplied from the
signal processing section 212. Also, the modulation/demodulation
section 211 synthesizes information on the basis of HARQ
information. For example, the modulation/demodulation section 211
properly synthesizes an original signal and a retransmission signal
at an intermediate stage of processing. The modulation/demodulation
section 211 supplies data that has undergone these processes to the
data processing section 202 or the control section 201.
In the case of signal transmission, the signal processing section
212 performs, on input from the modulation/demodulation section
211, signal processing used for space separation, as needed, thus
generating one or more transmission symbol streams. The signal
processing section 212 supplies the one or more transmission symbol
streams acquired to the respective wireless interface sections
214.
In the case of signal reception, the signal processing section 212
performs signal processing on the reception symbol streams input
from the respective wireless interface sections 214, thus
performing space decomposition of the streams as necessary. The
signal processing section 212 supplies the processed signal to the
modulation/demodulation section 211.
The channel estimation section 213 calculates complex channel gain
information of a propagation path on the basis of an input signal's
preamble portion and training signal portion from each of the
wireless interface sections 214. The channel estimation section 213
supplies the calculated complex channel gain information to the
modulation/demodulation section 211 and the signal processing
section 212 via the control section 201. The
modulation/demodulation section 211 employs the complex channel
gain information for the demodulation process. The signal
processing section 212 employs the complex channel gain information
for signal processing used for space separation.
In the case of signal transmission, the wireless interface section
214 converts input from the signal processing section 212 into an
analog signal, filters the analog signal, and upconverts the signal
to a carrier frequency, transmitting the processed signal to the
amplifier section 215. Also, in the case of signal reception, the
wireless interface section 214 performs, on input from the
amplifier section 215, processes opposite to processes at the time
of signal transmission, supplying the processed data to the signal
processing section 212 and the channel estimation section 213.
In the case of signal transmission, the amplifier section 215
amplifies the analog signal input from the wireless interface
section 214 to a given level of power, transmitting the analog
signal as a wireless signal via the antenna 216 (emitting the
signal into the air). Also, in the case of signal reception, the
amplifier section 215 receives a wireless signal via the antenna
216 (a signal transmitted through the air) and amplifies the
received signal to a given level of power, supplying the signal to
the wireless interface section 214. It should be noted that at
least one of the function of the amplifier section 215 in the case
of signal transmission or the function of the amplifier section 215
in the case of signal reception may be included in the wireless
interface section 214.
The power supply section 221 includes a battery power supply or a
stationary power supply, supplying power to each processing section
(the control section 201, the data processing section 202, and the
wireless communication section 203 (the modulation/demodulation
section 211 to the antenna 216)) of the communication apparatus
200. It should be noted that this supply of power may be controlled
by the control section 201.
<Modulation/Demodulation Section 211>
FIG. 3 illustrates a main configuration example regarding processes
performed by the modulation/demodulation section 211 at the time of
signal reception in the case where an original signal and a
retransmission signal are synthesized at an intermediate stage of
processing as HARQ-based synthesis. In this case, the
modulation/demodulation section 211 includes a demodulation section
231, a signal retention section 232, and a signal synthesis section
233 as components related to processes in the case of signal
reception as illustrated in FIG. 3.
The demodulation section 231 demodulates the original signal input
from the signal processing section 212 on the basis of the coding
and modulation schemes set by the control section 201. The
demodulation section 231 supplies the original data acquired by the
demodulation to any one of the data processing section 202, the
signal synthesis section 233, or the signal retention section 232
on the basis of the setting made by the control section 201.
For example, in the case of a signal not including HARQ-based
retransmission data, the demodulation section 231 performs
deinterleaving and other processes on the demodulated data,
supplying the processed demodulated data to the data processing
section 202. Also, the demodulation section 231 supplies the
demodulated data to the signal retention section 232 for retention.
The data processing section 202 determines whether the reception
has succeeded or failed by using error detection and other
techniques on the supplied demodulated data. In the case where the
data has not been received properly, the data processing section
202 controls the signal retention section 232 to continuously
retain the data.
Also, for example, in the case of a signal including HARQ-based
retransmission data, the demodulation section 231 supplies the
demodulated data to the signal retention section 232 for retention.
Also, the demodulation section 231 supplies the demodulated data to
the signal synthesis section 233.
The signal retention section 232 has an arbitrary storage medium
such as a semiconductor memory and retains the supplied demodulated
data in the storage medium. Also, the signal retention section 232
supplies the retained data to the signal synthesis section 233 in
response to a request from the signal synthesis section 233 or
other sections.
The signal synthesis section 233 reads out the demodulated data
(retained data) retained in the signal retention section 232 for
acquisition. Also, the signal synthesis section 233 synthesizes, by
vector addition or other methods, pieces of demodulated data
corresponding to the same data by using the retained data read out
from the signal retention section 232 and the demodulated data
(retransmission data) supplied from the demodulation section 231 in
accordance with a data identifier, a data order, and data time
included in HARQ information.
The signal synthesis section 233 performs deinterleaving and other
processes on the synthesized demodulated data, supplying the
processed demodulated data to the data processing section 202. The
data processing section 202 determines whether the reception of the
supplied demodulated data has succeeded or failed by using error
detection or other methods and controls, in the case where the data
was not properly received once again, the signal retention section
232 to retain the data.
It should be noted that in the case where the original data and the
retransmission data are synthesized as HARQ-based synthesis, the
data processing section 202 may retain the original data.
<Sequence>
A description will next be given of a communication flow in the
case where the communication apparatus 200 as described above is
applied to the base station 101 and the terminal apparatus 102 of
the communication system 100 illustrated in FIG. 1. FIG. 4 is a
diagram illustrating an example of a sequence in the case where
single user communication takes place using a polling frame
(hereinafter also referred to as a Poll frame) for all
communication. FIG. 4 illustrates communication between the base
station 101 (AP1) and the terminal apparatus 102-1 (STA1) as an
example.
In FIG. 4, the horizontal axis represents a time axis, the white
rectangles on each axis represent frames, and the parallelograms
represent random waiting time provided by a collision avoidance
mechanism. The solid line arrows extending from the frames indicate
that the arrows point to the destinations of the frames.
Before this sequence begins, the base station 101 (AP1) and the
terminal apparatus 102-1 (STA1), which is a subordinate unit of the
base station 101, perform a confirmation sequence for capability on
HARQ communication on the basis of HARQ information transmitted
from the receiving side of the retransmission signal illustrated in
the present working example. In other words, the base station 101
(AP1) and the terminal apparatus 102-1 (STA1), which is a
subordinate unit of the base station 101, exchange their capability
information regarding HARQ.
Also, before this sequence begins, the base station 101 (AP1) and
the terminal apparatus 102-1 (STA1), which is a subordinate unit of
the base station 101, may carry out a negotiation (size
negotiation) to decide a data unit length such as an MPDU in the
MAC layer. It should be noted that the data unit length may be an
integer multiple of a coding block unit at the time of block
coding.
The base station 101 (AP1) and the terminal apparatus 102-1 (STA1)
communicate on the basis of a normal channel access procedure. In
this example, the terminal apparatus 102-1 (STA1) acquires
transmission right first and transmits a signal to the base station
101 (AP1) (an arrow 301).
The base station 101 (AP1) that received the signal acquires data
such as an MPDU (Media Access Control Protocol Data Unit) by
performing a reception process on the signal and then determines
whether the data reception has succeeded or failed by performing
error detection. Thereafter, the base station 101 (AP1) stores
information based on whether the reception has succeeded or failed
in a frame such as block ack (BA (Block Ack)), transmitting the
frame to the terminal apparatus 102-1 (STA1) (an arrow 302).
Here, in the case where a signal whose demodulation has failed
exists, the base station 101 (AP1) treats the signal as an original
signal and retains, without discarding, at least part of the bit
strings of the original data corresponding to that original signal
or at least part of the original signal at an intermediate stage of
processing. For example, the signal retention section 232 retains
the original signal. This retained original signal will also be
referred to as a retained signal. It should be noted that in the
case where original data is retained, the original data will also
be referred to as retained data.
Then, the base station 101 (AP1) transmits, to the terminal
apparatus 102-1 (STA1), a Poll frame including HARQ information
(HARQ info), as a retransmission request signal (retransmission
request frame) requesting retransmission of a signal (an arrow
303).
HARQ information is information regarding the configuration of the
retransmission signal and includes information required to engage
in communication to which HARQ is applied (HARQ communication).
HARQ information will be described in detail later. The terminal
apparatus 102-1 (STA1) that received the Poll frame including HARQ
information generates data (retransmission data) regarding
requested information to be retransmitted (retransmission
information) in accordance with the HARQ information and generates
a signal including the retransmission data and new data (a signal
including a retransmission signal), transmitting the signal to the
base station 101 (AP1) (an arrow 304).
In the case where the data whose retransmission has been requested
had already been discarded, the terminal apparatus 102-1 (STA1) may
notify the requester that the data has already been discarded. For
example, Null data may be transmitted as this notice.
The base station 101 (AP1) that received the signal performs a
reception process on the signal in accordance with HARQ information
notified by the base station 101 (AP1) itself, thus extracting the
retransmission signal. The base station 101 (AP1) synthesizes
information by using the original signal and the retransmission
signal through HARQ, acquiring data such as an MPDU. For example,
the base station 101 (AP1) synthesizes the retained signal
(original signal) and the retransmission signal in the form of bit
strings of data such as an MPDU or at an intermediate stage of
processing before conversion into bit strings in accordance with
HARQ information and demodulates the resultant data or performs
other processes, thus acquiring data. Also, for example, the base
station 101 (AP1) synthesizes the retransmission data, acquired,
for example, by demodulating the retransmission signal, with the
retained data (original data) in accordance with HARQ
information.
The base station 101 (AP1) determines whether the data reception
has succeeded or failed by performing error detection on the
acquired data. Thereafter, the base station 101 (AP1) stores
information based on whether the reception has succeeded or failed
in a frame such as block ack (BA (Block Ack)), transmitting the
frame to the terminal apparatus 102-1 (STA1) (an arrow 305).
In the case where the reception has failed, the sequence from the
arrow 303 to the arrow 305 described above is repeated. It should
be noted that in the case where a notice (e.g., Null data) to the
effect that the data whose retransmission has been requested had
already been discarded is transmitted to the requester as described
above, the base station 101 (AP1) may terminate the retransmission
request on the basis of the notice. This suppresses increase in
unnecessary retransmission requests (requests that cannot be
responded to).
The sequence described above also holds in the case where the base
station 101 (AP1) and the terminal apparatus 102-1 (STA1) are
switched one to another (in the case where the base station 101
(AP1) acquires transmission right and transmits a signal to the
terminal apparatus 102-1 (STA1)). In other words, in the
description given above, the base station 101 (AP1) and the
terminal apparatus 102-1 (STA1) may be switched one to another.
Needless to say, the communication counterpart of the base station
101 (AP1) may be the terminal apparatus 102-2 (STA2). In other
words, in this case as well, communication can take place by using
a similar sequence.
<HARQ Information>
HARQ information includes information regarding the configuration
of a retransmission signal. This information regarding the
configuration of a retransmission signal may be information of any
kind and may include, for example, information regarding data whose
retransmission is requested. Also, this information regarding data
whose retransmission is requested may be information of any kind
and may include, for example, information regarding a data
identifier and information regarding a data length.
Information regarding the data identifier may be information of any
kind and may include, for example, an MPDU sequence number in the
MAC layer.
Information regarding the data length may be information of any
kind and may include, for example, a byte length of the MPDU whose
identifier is indicated by information regarding the data
identifier. Also, for example, information regarding data length
may include a block count or a byte length of the coding block
including, without excess or deficiency, the MPDU. Further, for
example, information regarding the data length may include
information such as signal time at an intermediate stage of
processing before conversion of the data into bit strings. Needless
to say, information regarding the data length may include a
plurality of these pieces of information. Also, information
regarding the data length may indirectly indicate a length of these
pieces of data.
Information regarding data whose retransmission is requested may
further include information regarding a data order. This
information regarding the data order may be information of any kind
and may include, for example, information regarding a data
connection order. Also, this information regarding the data order
may include, for example, a rule indicating an order of
retransmission data and new data. Needless to say, information
regarding the data order may include a plurality of these pieces of
information. Also, information regarding the data order may
indirectly indicate an order of these pieces of data.
Information regarding a configuration of a retransmission signal
may further include, for example, information regarding a setting
of information synthesis using an original signal and a
retransmission signal (i.e., information regarding a synthesis
setting through HARQ). This information regarding an HARQ setting
may be information of any kind and may include, for example, a
notice to the effect that HARQ is used. Also, for example,
information regarding the HARQ setting may include an identifier of
an HARQ stream, which is a stream such as an image or sound to be
subjected to HARQ. By using this identifier, it is possible to
suppress erroneous synthesis of retransmission data with irrelevant
stream data.
Also, information regarding the HARQ setting may include an HARQ
scheme notice (notice of a synthesis scheme used) such as Chase
Combining or Incremental Redundancy. A synthesis specification
becomes apparent from this notice, thus allowing for generation of
retransmission data with higher efficiency.
Needless to say, information regarding the HARQ setting may include
a plurality of these pieces of information.
<Frame Format of HARQ Information>
FIG. 5 illustrates an example of a frame format by which HARQ
information is notified, the HARQ information being transmitted
from the communication apparatus 200 on the side requesting
retransmission of a signal as described above (receiving side)
(base station 101 (AP1) in the case of the example illustrated in
FIG. 4) to the communication apparatus 200 on the signal
retransmission side (terminal apparatus 102-1 (STA1) in the case of
the example illustrated in FIG. 4) as described above.
As illustrated in FIG. 5, a frame 320 transmitting HARQ information
has three frames, namely, an HARQ control 321 (HARQ Control), a
sequence number 322 (Sequence Number), and an HARQ length 323 (HARQ
Length).
The HARQ control 321 (HARQ Control) includes information regarding
the HARQ setting. The sequence number 322 (Sequence Number)
includes information regarding an identifier of data to be
transmitted. The HARQ length 323 (HARQ Length) includes information
regarding a length of data to be transmitted.
It should be noted that the sequence number 322 (Sequence Number)
and the HARQ length 323 (HARQ Length) may be repeated as many times
as the number of pieces of data whose retransmission is requested
on the basis of HARQ information.
FIG. 6 is a diagram illustrating another configuration example of a
frame format by which HARQ information is notified. A frame 330
transmitting HARQ information, which is illustrated in FIG. 6, has
four frames, namely, an HARQ control 331 (HARQ Control), a starting
sequence number 332 (Starting Sequence Number), a sequence number
bitmap 333 (Sequence Number Bitmap), and an HARQ length 334 (HARQ
Length).
The HARQ control 331 (HARQ Control) includes information similar to
that of the HARQ control 321 illustrated in FIG. 5. The HARQ length
334 (HARQ Length) includes information similar to that of the HARQ
length 323 (HARQ Length) illustrated in FIG. 5.
The starting sequence number 332 (Starting Sequence Number)
includes an identifier of a first piece of a plurality of pieces of
data whose retransmission is requested on the basis of HARQ
information.
The sequence number bitmap 333 (Sequence Number Bitmap) includes an
identifier of a second or succeeding piece of the plurality of
pieces of data as information in bitmap (Bitmap) format relative to
the identifier of the first piece of data as a reference.
It should be noted that the HARQ length 334 (HARQ Length) may be
repeated as many times as the number of pieces of data whose
retransmission is requested on the basis of HARQ information. This
frame 330 can store information more efficiently than the frame 320
illustrated in FIG. 5 in the case where a plurality of identifiers
is stored.
Also, transmitting, as HARQ information, such information as
described above with reference to FIGS. 5 and 6 allows for the
communication apparatus 200 on the signal retransmission side to
generate a signal meeting the requested specification on the basis
of this HARQ information and retransmit the signal.
It should be noted that the frame format by which HARQ information
is notified is arbitrary and is not limited to the example
described above. For example, a frame by which HARQ information is
notified may include information other than the above.
Also, a frame by which HARQ information is notified as described
above (the frame 320 or the frame 330) may be connected to a Poll
frame (or a Trigger frame which will be described later) and
transmitted or may be transmitted as part of a Poll frame (or a
Trigger frame). Also, a Poll frame (or a Trigger frame) that
includes, as part thereof, a frame by which HARQ information is
notified may be connected to other Poll frame (or Trigger frame)
that does not include any frame by which HARQ information is
notified and transmitted.
<Poll Frame>
FIG. 7 illustrates an example of a Poll frame that includes, as
part thereof, a frame by which HARQ information is notified. As
illustrated in FIG. 7, a Poll frame 340 including, as part thereof,
a frame by which HARQ information is notified has, for example, a
frame control 341 (Frame Control), a duration 342 (Duration), a
receiving address 343 (RA), a transmitting address 344 (TA), a
response offset 345 (Response Offset), an HARQ information 346
(HARQ Info), and a frame check sequence 347 (FCS (Frame Check
Sequence)).
The frame control 341 (Frame Control) includes information
regarding MAC frame control. The duration 342 (Duration) includes
information regarding an anticipated duration for which to use a
wireless line. The receiving address 343 (RA) includes information
regarding addresses such as a broadcast address. The transmitting
address 344 (TA) includes information regarding a MAC address of
the communication apparatus 200, which is the sender.
The response offset 345 (Response Offset) includes information
regarding time to signal transmission after reception of a Poll
frame. The HARQ information 346 (HARQ Info) includes the frame 320
or the frame 330 (i.e., frame by which HARQ information is
notified) described above. The frame check sequence 347 (FCS (Frame
Check Sequence)) includes information for carrying out frame error
detection and correction.
As described above, HARQ information can be transmitted by using a
Poll frame. This makes HARQ information highly compatible with
existing communication standards, thus ensuring easy
realization.
<Flow of the Retransmission Data Transmission Process>
A description will next be given of the flow of processes performed
by the communication apparatus 200 that handles the sequence as
described above. A description will first be given of an example of
the flow of a retransmission data transmission process carried out
by the communication apparatus 200 on the signal retransmission
side (terminal apparatus 102-1 (STA1) in the case of the example
illustrated in FIG. 4) with reference to the flowchart illustrated
in FIG. 8.
When the retransmission data transmission process begins, the
communication apparatus 200 exchanges, in step S101, capability
information regarding HARQ-based communication (HARQ communication)
with the destination of the signal (i.e., the communication
apparatus 200, which is the communication counterpart). More
specifically, the control section 201 manages capability
information regarding HARQ communication of the communication
apparatus 200 in question. The control section 201 supplies the
capability information to the wireless communication section 203
via the data processing section 202, causing the wireless
communication section 203 to exchange the capability information
with the communication apparatus 200, which is the communication
counterpart. As a result of this exchange of capability
information, the communication apparatus 200 can find out about the
capability of the communication apparatus 200, which is the
communication counterpart, regarding HARQ communication (for
example, whether or not the communication counterpart is capable of
HARQ communication).
The control section 201 determines, in step S102, whether or not to
negotiate the MPDU size with the communication apparatus 200, which
is the communication counterpart. For example, in the case where it
is determined that the communication apparatus 200, which is the
communication counterpart, is capable of HARQ communication and
that the control section 201 will proceed with MPDU size
negotiation, the process proceeds to step S103.
In step S103, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to negotiate
the MPDU size with the communication apparatus 200, which is the
communication counterpart. When the process in step S103 ends, the
process proceeds to step S104. Also, in the case where it is
determined that the MPDU size will not be negotiated in step S102,
the process in step S103 is omitted, and the process proceeds to
step S104.
In step S104, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to transmit
a signal and receive a signal including reception success/failure
information transmitted from the communication apparatus 200, which
is the communication counterpart, in response to the signal
transmission. For example, in the case of the sequence illustrated
in FIG. 4, the exchange of signals as indicated by the arrow 301
and the arrow 302 takes place.
In step S105, the control section 201 determines whether or not a
retransmission request signal including HARQ information
(transmission request frame) has been received from the
communication apparatus 200, which is the communication
counterpart. For example, in the case where it is determined that a
Poll frame including HARQ information has been received as
indicated by the arrow 303 in the sequence example illustrated in
FIG. 4, the process proceeds to step S106.
In step S106, the control section 201 extracts HARQ information
from the data of the received Poll frame and generates
retransmission information on the basis of the extracted HARQ
information. The control section 201 supplies the retransmission
information to the data processing section 202, causing the data
processing section 202 to generate retransmission data. The control
section 201 controls the wireless communication section 203 to
generate a signal including the retransmission data and new data,
transmitting the signal to the communication apparatus 200, which
is the communication counterpart, as indicated, for example, by the
arrow 304 in the sequence example illustrated in FIG. 4. In other
words, the communication apparatus 200 creates a signal including
the retransmission data and new data for transmission such that the
signal includes data as specified by HARQ information.
It should be noted that in the case where the data whose
retransmission has been requested had already been discarded, the
control section 201 may control the data processing section 202 and
the wireless communication section 203 to transmit Null data in
place of transmitting a signal including the retransmission data
and new data.
In step S107, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to receive a
signal including reception success/failure information transmitted
from the communication apparatus 200, which is the communication
counterpart, in response to the signal transmission as indicated,
for example, by the arrow 305 in the sequence example illustrated
in FIG. 4.
When the process in step S107 ends, the retransmission data
transmission process ends. Also, in the case where it is determined
in step S105 that a retransmission request signal including HARQ
information has yet to be received from the communication apparatus
200, which is the communication counterpart, the retransmission
data transmission process ends.
It should be noted that in the case where it is determined on the
basis of reception success/failure information received in step
S107 that the communication counterpart has failed in the reception
of a retransmission signal, the communication apparatus 200 may
repeat the processes from step S105 to step S107 until the
communication counterpart successfully receives a retransmission
signal, until a given period of time elapses, or until the data is
discarded.
<Flow of the Retransmission Data Reception Process>
A description will next be given of an example of a flow of a
retransmission data reception process performed by the
communication apparatus 200 on the signal retransmission requesting
side (base station 101 (AP1) in the case of the example illustrated
in FIG. 4) with reference to the flowchart illustrated in FIG.
9.
When the retransmission data reception process begins, the
communication apparatus 200 exchanges, in step S121, capability
information regarding HARQ communication with the sender of the
signal (i.e., the communication apparatus 200, which is the
communication counterpart). More specifically, the control section
201 manages capability information regarding HARQ communication of
the communication apparatus 200 in question. The control section
201 supplies the capability information to the wireless
communication section 203 via the data processing section 202,
causing the wireless communication section 203 to exchange the
capability information with the communication apparatus 200, which
is the communication counterpart. As a result of this exchange of
capability information, the communication apparatus 200 can find
out about the capability of the communication apparatus 200, which
is the communication counterpart, regarding HARQ communication (for
example, whether or not the communication counterpart is capable of
HARQ communication).
The control section 201 determines, in step S122, whether or not to
negotiate the MPDU size with the communication apparatus 200, which
is the communication counterpart. For example, in the case where it
is determined that the communication apparatus 200, which is the
communication counterpart, is capable of HARQ communication and
that the control section 201 will proceed with MPDU size
negotiation, the process proceeds to step S123.
In step S123, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to negotiate
the MPDU size with the communication apparatus 200, which is the
communication counterpart. When the process in step S123 ends, the
process proceeds to step S124. Also, in the case where it is
determined that the MPDU size will not be negotiated in step S122,
the process in step S123 is omitted, and the process proceeds to
step S124.
In step S124, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to receive a
signal normally transmitted from the sender. In step S125, the
control section 201 controls the data processing section 202 and
the wireless communication section 203 to acquire data from the
received signal, perform error detection on one or more pieces of
the acquired data such as an MPDU, and determine whether the data
reception has succeeded or failed.
In the case where it is determined that the demodulation of data
has failed as a result of the process in step S125, the control
section 201 controls the data processing section 202 or the
wireless communication section 203 in step S126 to retain, by
treating the signal whose demodulation has failed as an original
signal, at least part of the original signal at an intermediate
stage of processing or at least part of the bit strings of the
original data corresponding to the original signal without
discarding the original signal.
In step S127, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to transmit
reception success/failure information corresponding to the original
data.
In step S128, the control section 201 determines whether or not to
transmit a transmission request frame including HARQ information to
the sender of the original signal. In the case where it is
determined that a transmission request frame is transmitted, the
process proceeds to step S129.
In step S129, the control section 201 calculates at least any one
of start and end points of data that was not properly received
(data whose demodulation has failed), start and end points of a
coding unit including an error, or start and end points of a bit
string including an error. Then, the control section 201 sets
(generates) HARQ information on the basis of a calculation result
thereof such that the same data, the coding unit, or the bit string
can be estimated in the retransmitted signal. The control section
201 supplies the HARQ information to the data processing section
202 and controls the data processing section 202 and the wireless
communication section 203 to transmit a Poll frame including the
HARQ information to the sender of the retransmission data.
In step S130, the control section 201 controls the wireless
communication section 203 to receive a signal including new data
and the retransmission data generated on the basis of the
transmitted HARQ information.
In step S131, the control section 201 controls the data processing
section 202 and the wireless communication section 203
(modulation/demodulation section 211) to synthesize information by
using the retransmission data (or the retransmission signal) and
retained data (or the retained signal) on the basis of the HARQ
information.
In step S132, the control section 201 controls the data processing
section 202 and the wireless communication section 203 to generate
a signal including reception success/failure information for the
signal and transmit the signal to the sender of the retransmission
data.
When the process in step S132 ends, the retransmission data
reception process ends. Also, in the case where it is determined in
step S128 that a transmission request frame (Poll frame) will be
not be transmitted, the processes from step S129 to step S132 are
omitted, and the retransmission data reception process ends.
It should be noted that in the case where the demodulation of the
signal received in step S130 fails, the processes from step S128 to
step S132 may be repeated until a retransmission signal is
successfully received, until a given period of time elapses, or
until given data (e.g., Null data) is received.
By performing each of the processes as described above, the
communication apparatus 200 can realize information synthesis by
using an original signal and a retransmission signal for
retransmitting information of the original signal whose
demodulation has failed, in wireless communication with its
physical layer and MAC layer independent of each other, without
requiring additional information in a physical layer header. This,
therefore, suppresses increase in overhead. Further, this
suppresses increase in buffer consumption and power consumption.
Further, this suppresses increase in resource consumption
attributable to retransmission.
<Sequence>
Although the description has been given above by taking, as an
example, the sequence illustrated in FIG. 4, the example
illustrated in FIG. 4 is merely an example, and the present
technology is applicable to other sequences in addition to the
sequence illustrated in FIG. 4.
For example, single user communication using a Poll frame may be
carried out in part of communication. A sequence example in this
case is illustrated in FIG. 10. In the case of the example
illustrated in FIG. 10, the base station 101 (AP1) engages in
uplink multi-user communication using a trigger frame (hereinafter
referred to as a Trigger frame) with the terminal apparatus 102-1
(STA1) and the terminal apparatus 102-2 (STA2), which are
subordinate units of the base station 101. It should be noted,
however, that a retransmission request is issued by using a Poll
frame that is transmitted to a single terminal as in the case
illustrated in FIG. 4.
Also in this case, capability information regarding HARQ
communication may be exchanged and the MPDU size in the MAC layer
may be negotiated between the communication apparatuses 200
(between the base station 101 (AP1) and the terminal apparatus
102-1 (STA1) and between the base station 101 (AP1) and the
terminal apparatus 102-2 (STA2)) before the present sequence begins
as in the case of the example illustrated in FIG. 4.
The base station 101 (AP1) transmits, to the terminal apparatus
102-1 (STA1) and the terminal apparatus 102-2 (STA2), a Trigger
frame including information for carrying out uplink multi-user
communication (UL OFDMA, UL MU-MIMO) (a terminal identifier, a
frequency/space resource, and so on), thus initiating an uplink
multi-user communication sequence (an arrow 361 and an arrow
362).
When this Trigger frame is received, the terminal apparatus 102-1
(STA1) and the terminal apparatus 102-2 (STA2) proceed with uplink
multi-user transmission on the basis of information included in the
Trigger frame (an arrow 363 and an arrow 364).
The base station 101 (AP1) that received a signal transmitted
through uplink multi-user transmission acquires one or more pieces
of data such as an MPDU by performing a reception process on the
signal, carrying out error detection and determining whether the
data reception has succeeded or failed.
Thereafter, the base station 101 (AP1) stores information based on
whether the reception has succeeded or failed in a multi-STA block
ack (M-BA (Multi-STA Block Ack)), transmitting the frame to the
terminal apparatus 102-1 (STA1) and the terminal apparatus 102-2
(STA2) (an arrow 365 and an arrow 366).
Here, in the case where a signal whose demodulation has failed
exists, the base station 101 (AP1) treats the signal as an original
signal and retains, without discarding, at least part of the bit
strings of the original data corresponding to the original signal
or at least part of the original signal at an intermediate stage of
processing. For example, the signal retention section 232 retains
the original signal.
Then, as in the case of the example illustrated in FIG. 4, the base
station 101 (AP1) transmits, to the sender of the original signal
(the terminal apparatus 102-1 (STA1) or the terminal apparatus
102-2 (STA2)), a Poll frame including HARQ information (HARQ info)
as a retransmission request signal (retransmission request frame)
requesting the signal retransmission. In the example illustrated in
FIG. 10, it is assumed that the demodulation of a signal from the
terminal apparatus 102-1 (STA1) has failed, and the base station
101 (AP1) transmits a Poll frame including HARQ information (HARQ
info) to the terminal apparatus 102-1 (STA1) (an arrow 367).
It should be noted that in the case where the data whose
retransmission has been requested had already been discarded, the
terminal apparatus 102 may notify the requester that the data has
already been discarded. For example, Null data may be transmitted
as this notice.
As in the case illustrated in FIG. 4, the terminal apparatus 102-1
(STA1) that received the Poll frame including HARQ information
generates data (retransmission data) regarding requested
information to be retransmitted (retransmission information) in
accordance with the HARQ information and generates a signal
including the retransmission data and new data (a signal including
a retransmission signal), transmitting the signal to the base
station 101 (AP1) (an arrow 368).
As in the case illustrated in FIG. 4, the base station 101 (AP1)
that received the signal performs a reception process on the signal
in accordance with HARQ information notified by the base station
101 (AP1) itself, thus extracting the retransmission signal and
synthesizing information through HARQ. In other words, the base
station 101 (AP1) synthesizes information by using the retained
signal and the retransmission signal.
As in the case illustrated in FIG. 4, the base station 101 (AP1)
performs error detection on the acquired data and determines
whether or not the reception of the acquired data has succeeded or
failed. Thereafter, the base station 101 (AP1) stores information
based on whether the reception has succeeded or failed in a frame
such as block ack (BA (Block Ack)), transmitting the frame to the
terminal apparatus 102-1 (STA1) (an arrow 369).
In the case where the reception has failed, the sequence from the
arrow 367 to the arrow 369 described above is repeated. It should
be noted that in the case where a notice (e.g., Null data) to the
effect that the data whose retransmission was requested had already
been discarded is transmitted to the requester as described above,
the base station 101 (AP1) may terminate the retransmission request
on the basis of the notice. This suppresses increase in unnecessary
retransmission requests (requests that cannot be responded to).
The sequence described above also holds in the case where the base
station 101 (AP1) and the terminal apparatus 102-1 (STA1) are
switched one to another (in the case where the base station 101
(AP1) acquires transmission right and transmits a signal to the
terminal apparatus 102-1 (STA1) or the terminal apparatus 102-2
(STA2)). In other words, in the description given above, the base
station 101 (AP1) and the terminal apparatus 102 may be switched
one to another. Needless to say, in the case where the base station
101 (AP1) fails in the demodulation of a signal from the terminal
apparatus 102-2 (STA2), communication can take place by using a
similar sequence.
<Sequence>
Further, for example, uplink multi-user communication using a
Trigger frame may be carried out for all communication. A sequence
example in this case is illustrated in FIG. 11. In the case of the
example illustrated in FIG. 11, communication is basically carried
out by using a sequence similar to that in the case of the example
illustrated in FIG. 10, and a retransmission request is also issued
by using a Trigger frame.
Also in this case, capability information regarding HARQ
communication may be exchanged and the MPDU size in the MAC layer
may be negotiated between the communication apparatuses 200
(between the base station 101 (AP1) and the terminal apparatus
102-1 (STA1) and between the base station 101 (AP1) and the
terminal apparatus 102-2 (STA2)) before the present sequence begins
as in the cases of the examples illustrated in FIGS. 4 and 10.
Then, the base station 101 (AP1) transmits, to the terminal
apparatus 102-1 (STA1) and the terminal apparatus 102-2 (STA2), a
Trigger frame including information for carrying out uplink
multi-user communication (UL OFDMA, UL MU-MIMO) (a terminal
identifier, a frequency/space resource, and so on), thus initiating
an uplink multi-user communication sequence (an arrow 381 and an
arrow 382).
When this Trigger frame is received, the terminal apparatus 102-1
(STA1) and the terminal apparatus 102-2 (STA2) proceed with uplink
multi-user transmission on the basis of information included in the
Trigger frame (an arrow 383 and an arrow 384).
The base station 101 (AP1) that received a signal transmitted
through uplink multi-user transmission acquires one or more pieces
of data such as an MPDU by performing a reception process on the
signal, carrying out error detection and determining whether the
data reception has succeeded or failed.
Thereafter, the base station 101 (AP1) stores information based on
whether the reception has succeeded or failed in a frame such as a
multi-STA block ack (M-BA (Multi-STA Block Ack)), transmitting the
frame to the terminal apparatus 102-1 (STA1) and the terminal
apparatus 102-2 (STA2) (an arrow 385 and an arrow 386).
Here, in the case where a signal whose demodulation has failed
exists, the base station 101 (AP1) treats the signal as an original
signal and retains, without discarding, at least part of the bit
strings of the original data corresponding to the original signal
or at least part of the original signal at an intermediate stage of
processing. For example, the signal retention section 232 retains
the original signal.
The sequence is similar to that in the case of the example
illustrated in FIG. 10 up to this point.
Here, the base station 101 (AP1) transmits, to the senders of the
original signal (the terminal apparatus 102-1 (STA1) and the
terminal apparatus 102-2 (STA2)), a Trigger frame including HARQ
information (HARQ info) as a retransmission request signal
(retransmission request frame) requesting retransmission of a
signal in order to carry out new uplink multi-user communication
including data whose demodulation has failed (an arrow 391 and an
arrow 392).
When this Trigger frame including HARQ information is received,
each of the terminal apparatus 102-1 (STA1) and the terminal
apparatus 102-2 (STA2) generates data (retransmission data)
regarding requested information to be retransmitted (retransmission
information) in accordance with the HARQ information and generates
a signal including the retransmission data and new data (a signal
including a retransmission signal), transmitting the signal to the
base station 101 (AP1) (an arrow 393 and an arrow 394).
It should be noted that in the case where the data whose
retransmission has been requested had already been discarded, the
terminal apparatus 102 may notify the requester that the data has
already been discarded. For example, Null data may be transmitted
as this notice.
The base station 101 (AP1) that received the signal performs a
reception process on the signal in accordance with HARQ information
notified by the base station 101 (AP1) itself, thus extracting the
retransmission signal as in the cases illustrated in FIGS. 4 and
10. The base station 101 (AP1) synthesizes information by using the
original signal and the retransmission signal through HARQ,
acquiring data such as an MPDU. For example, the base station 101
(AP1) synthesizes the retained signal (original signal) and the
retransmission signal in the form of bit strings of data such as an
MPDU or at an intermediate stage of processing before conversion
into bit strings in accordance with HARQ information and
demodulates the resultant data or performs other processes, thus
acquiring data. Also, for example, the base station 101 (AP1)
synthesizes the retransmission data, acquired, for example, by
demodulating the retransmission signal, with the retained data
(original data) in accordance with HARQ information.
The base station 101 (AP1) determines whether the data reception
has succeeded or failed by performing error detection on the
acquired data. Thereafter, the base station 101 (AP1) stores
information based on whether the reception has succeeded or failed
in a frame such as multi-STA block ack (M-BA (Multi-STA Block
Ack)), transmitting the frame to the terminal apparatus 102-1
(STA1) and the terminal apparatus 102-2 (STA2) (an arrow 395 and an
arrow 396).
In the case where the reception has failed, the sequence from the
arrow 391 to the arrow 396 described above is repeated. It should
be noted that in the case where a notice (e.g., Null data) to the
effect that the data whose retransmission was requested had already
been discarded is transmitted to the requester as described above,
the base station 101 (AP1) may terminate the retransmission request
on the basis of the notice. This suppresses increase in unnecessary
retransmission requests (requests that cannot be responded to).
It should be noted that, in the case of the example illustrated in
FIG. 11, only the base station 101, which is the parent unit, can
transmit a Trigger frame. Therefore, this sequence is applicable
only in the case where data is transmitted from the terminal
apparatus 102 to the base station 101 as in FIG. 11.
<Trigger frame>
FIGS. 12A and 12B illustrate an example of a Trigger frame that
includes, as part thereof, a frame by which HARQ information is
notified. As illustrated in A of FIG. 12A, a Trigger frame 410 has,
for example, a frame control 411 (Frame Control), a duration 412
(Duration), a receiving address 413 (RA), a transmitting address
414 (TA), common information 415 (Common Info), user information
416 (Per User Info), padding 417 (Padding), and a frame check
sequence 418 (FCS).
The frame control 411 stores information similar to that in the
case of the frame control 341. The duration 412 stores information
similar to that in the case of the duration 342. The receiving
address 413 stores information similar to that in the case of the
receiving address 343. The transmitting address 414 stores
information similar to that in the case of the transmitting address
344.
The common information 415 stores information (PPDU length and
physical layer frame header information) that can be referenced by
all the terminal apparatuses 102 (all STAs) that received the
Trigger frame. The user information 416 stores information
individually referenced by the terminal apparatuses 102 (STAs) that
received the Trigger frame.
The padding 417 stores information for adjusting the frame length.
The frame check sequence 418 stores information similar to that in
the case of the frame check sequence 347.
As illustrated in FIG. 12B, the user information 416 (Per User
Info) has, for example, a user identifier 431 (User Identifier), an
RU allocation 432 (RU (Resource Unit) Allocation), a coding type
433 (Coding Type), a modulation coding scheme 434 (MCS (Modulation
Coding Scheme)), a dual carrier modulation (Dual Carrier
Modulation), an SS allocation (SS allocation) 436, an HARQ
information 437 (HARQ info), and a basic 438 (Basic).
The user identifier 431 (User Identifier) stores information
regarding an identifier (Association ID) of the terminal apparatus
102 (STA). The RU allocation 432 (RU (Resource Unit) Allocation)
stores information regarding a frequency (Resource Unit) used for
transmission.
The coding type 433 (Coding Type) stores information regarding a
coding type used for the signal to be transmitted. The modulation
coding scheme 434 (MCS (Modulation Coding Scheme)) stores
information regarding an MCS used for the signal to be transmitted.
The dual carrier modulation (DCM (Dual Carrier Modulation)) stores
information regarding whether or not DCM is used for the signal to
be transmitted.
As described above, the transmission of information regarding a
coding and decoding scheme and a modulation and demodulation scheme
together with HARQ information allows for the communication
apparatus 200 on the receiving side of retransmission data to
acquire retransmission data compliant with a desired coding and
decoding scheme and modulation and demodulation scheme. In other
words, the communication apparatus 200 on the transmitting side of
retransmission data can transmit retransmission data compliant with
a desired coding and decoding scheme and modulation and
demodulation scheme.
The SS allocation (SS allocation) 436 stores information regarding
a spatial stream of the signal to be transmitted. The HARQ
information 437 (HARQ info) stores information similar to that in
the case of the HARQ information 346. The basic 438 (Basic)
includes information used in the case where a normal transmission
request, which is not a request for retransmission based on HARQ
information, is issued. In the case where a normal retransmission
request is not issued, Basic may be omitted.
Also, for example, information specifying the communication
apparatus 200, which is the destination, as does a BSS (Basic
Service Set) identifier, may be transmitted together with HARQ
information. This prevents transmission of retransmission requests
(transmission frames) to the wrong communication apparatuses 200
(transmission of retransmission signals from the communication
apparatuses 200 that are not communication counterparts).
As described above, HARQ information can be transmitted by using a
Trigger frame. Therefore, high compatibility is achieved with
existing communication standards, thus ensuring easy
realization.
<Effect>
As described above, the application of the present technology
realizes HARQ-based retransmission in a communication system in
which a physical layer and a transport layer are independent of
each other. The physical layer handles modulation and demodulation
processes and coding and decoding processes on received signals.
The transport layer includes a MAC layer that identifies details
and an order of signals. Also, HARQ-based retransmission can be
realized without adding information to a physical layer header.
Also, a suitable data unit size can be used to realize HARQ-based
retransmission.
Also, the receiving side decides on its own how to use HARQ. This
eliminates the need for the receiving side to be on standby
constantly for HARQ processes, thus contributing to reduced buffer
consumption and power consumption. Also, it becomes possible to
detect data discarded by the transmitting side, thus suppressing
buffer consumption.
Also, the use of HARQ makes it possible to suppress resource
consumption attributable to retransmission. This makes it possible
to achieve improved communication quality, improved throughput,
reduced error rate, reduced power consumption, increased number of
units accommodated, and reduced interference of the system as a
whole.
As described above, the application of the present technology
allows for synthesis of information using an original signal and a
retransmission signal for retransmitting information of the
original signal whose demodulation has failed, in wireless
communication with independent physical layer and MAC layer.
It should be noted that although the description has been given
above by taking, as an example, a wireless LAN, the present
technology can find application in any wireless communication with
independent physical layer and MAC layer.
2. Others
<Computer>
The above series of processes can be performed by hardware or
software. Also, some of the processes can be performed by hardware,
and other processes can be performed by software. In the case where
the series of processes is performed by software, the program
included in the software is installed to a computer. Here, the
computer includes a computer incorporated in dedicated hardware and
a general-purpose personal computer capable of executing various
functions by installing various types of programs.
FIG. 13 is a block diagram illustrating a hardware configuration
example of a computer for performing the above series of processes
by using a program.
In a computer 900 illustrated in FIG. 13, a CPU (Central Processing
Unit) 901, a ROM (Read Only Memory) 902, and a RAM (Random Access
Memory) 903 are connected to each other via a bus 904.
An input-output interface 910 is also connected to the bus 904. An
input section 911, an output section 912, a storage section 913, a
communication section 914, and a drive 915 are connected to the
input-output interface 910.
The input section 911 includes, for example, a keyboard, a mouse, a
microphone, a touch panel, an input terminal, and so on. The output
section 912 includes, for example, a display, a speaker, an output
terminal, and so on. The storage section 913 includes, for example,
a hard disk, a RAM disk, a non-volatile memory, and so on. The
communication section 914 includes, for example, a network
interface. The drive 915 drives a removable medium 921 such as a
magnetic disk, an optical disc, a magneto-optical disk, or a
semiconductor memory.
In the computer configured as described above, the series of
processes described above is performed as the CPU 901 loads the
program stored in the storage section 913 into the RAM 903 via the
input-output interface 910 and the bus 904 for execution, for
example. The RAM 903 also stores, as appropriate, data required for
the CPU 901 to perform various processes.
The program executed by the computer (CPU 901) can be recorded, for
example, to the removable medium 921 as a package medium or other
media for use. In this case, the program can be installed to the
storage section 913 via the input-output interface 910 by inserting
the removable medium 921 into the drive 915. Also, this program can
be provided via a wired or wireless transmission medium such as a
local area network, the Internet, or digital satellite
broadcasting. In this case, the program can be received by the
communication section 914 and installed to the storage section 913.
In addition to the above, this program can be installed in advance
to the ROM 902 or the storage section 913.
<Supplement>
An embodiment of the present technology is not limited to that
described above and may be altered in various ways without
departing from the gist of the present technology.
For example, the present technology can be carried out as any kind
of components included in an apparatus or a system such as a
processor as a system LSI (Large Scale Integration), a module using
the plurality of processors, a unit using a plurality of the
modules, a set to which other functions have been added to the
unit, and so on (i.e., component included as part of the
apparatus).
It should be noted that, in the present specification, the term
"system" refers to a set of a plurality of components (e.g.,
apparatuses, modules (parts)), and it does not matter whether or
not all the components are provided in the same housing. Therefore,
a plurality of apparatuses accommodated in separate housings and
connected to each other via a network and a single apparatus having
a plurality of modules accommodated in a single housing are both
systems.
Also, for example, a component described as a single apparatus (or
a processing section) may be divided into a plurality of
apparatuses (processing sections). Conversely, components described
above as a plurality of apparatuses (processing sections) may be
combined into a single apparatus (or a processing section). Also, a
component other than those described above may be added to each of
the apparatuses (or each of the processing sections). Further, as
long as the components or operations of the system as a whole
remain substantially the same, some components of a certain
apparatus (or a processing section) may be included in components
of another apparatus (or another processing section).
Also, for example, the present technology can have a cloud
computing configuration in which one function is processed by a
plurality of apparatuses via a network in a shared and cooperative
manner.
Also, for example, the above program can be executed by an
arbitrary apparatus. In this case, it is only necessary to ensure
that the apparatus has required functions (e.g., functional blocks)
and can gain required information.
Also, for example, each of the steps described in the above
flowcharts can be performed not only by a single apparatus but also
by a plurality of apparatuses in a shared manner. Further, in the
case where a single step includes a plurality of processes, the
plurality of processes included in the single step can be performed
not only by a single apparatus but also by a plurality of
apparatuses in a shared manner. In other words, the plurality of
processes included in a single step can be performed as processes
of a plurality of steps. Conversely, the processes described as the
plurality of steps can be combined and executed as a single
step.
It should be noted that the program executed by the computer may
perform the processes chronologically according to the order
described in the present specification, may perform in parallel, or
may perform when necessary as when invoked. In other words, unless
inconsistency arises, the processes of the respective steps may be
performed in an order different from the above order. Further, the
processes of the steps defining this program may be performed in
parallel with those of another program or combined and performed
together with those of another program.
Each of the plurality of present technologies described in the
present specification can be independently carried out alone unless
inconsistency arises. Needless to say, any two or more of the
plurality of present technologies can be used in combination. For
example, some or all of the present technologies described in any
one of the embodiments can be combined and performed together with
some or all of the present technologies described in other
embodiments. Also, some or all of the arbitrary present
technologies described above can be carried out in combination with
other technologies not described above.
The present technologies can also have the following
configurations.
(1) A communication apparatus including:
a communication section adapted to transmit information regarding a
configuration of a retransmission signal for retransmitting
information of an original signal whose demodulation has failed to
a sender of the retransmission signal and receive the
retransmission signal transmitted from the sender on the basis of
the information regarding the configuration of the retransmission
signal transmitted.
(2) The communication apparatus of feature (1), in which
the information regarding the configuration of the retransmission
signal includes information regarding data whose retransmission is
requested.
(3) The communication apparatus of feature (2), in which
the information regarding data whose retransmission is requested
includes information regarding an identifier of the data and
information regarding a length of the data.
(4) The communication apparatus of feature (3), in which
the information regarding the identifier of the data includes a
sequence number of an MPDU (MAC Protocol Data Unit) in a MAC (Media
Access Control) layer.
(5) The communication apparatus of feature (3) or (4), in which
the information regarding the length of the data includes a byte
length of the MPDU (MAC Protocol Data Unit).
(6) The communication apparatus of any one of features (3) to (5),
in which
the information regarding the length of the data includes a block
count or a byte length of a coding block including, without excess
or deficiency, the MPDU (MAC Protocol Data Unit).
(7) The communication apparatus of any one of features (3) to (6),
in which
the information regarding the length of the data includes time of a
signal at an intermediate stage of processing until conversion of
the data into bit strings.
(8) The communication apparatus of any one of features (3) to (7),
in which
the information regarding the data whose retransmission is
requested further includes information regarding an order of the
data.
(9) The communication apparatus of feature (8), in which
the information regarding the order of the data includes
information regarding a connection order of the data.
(10) The communication apparatus of feature (8) or (9), in
which
the information regarding the order of the data includes
information regarding a rule indicating an order of the data and
new data.
(11) The communication apparatus of any one of features (2) to
(10), in which
the information regarding the configuration of the retransmission
signal further includes information regarding a setting of
information synthesis using the original signal and the
retransmission signal.
(12) The communication apparatus of feature (11), in which
the information regarding the synthesis setting includes a notice
to the effect that the synthesis will be performed.
(13) The communication apparatus of feature (11) or (12), in
which
the information regarding the synthesis setting includes an
identifier of a stream to be subjected to the synthesis.
(14) The communication apparatus of any one of features (11) to
(13), in which
the information regarding the synthesis setting includes
information regarding a scheme of the synthesis.
(15) The communication apparatus of any one of features (1) to
(14), in which
the communication section transmits the information regarding the
configuration of the retransmission signal as part of a
transmission request frame of the retransmission signal.
(16) The communication apparatus of feature (15), in which
the transmission request frame is a Trigger frame.
(17) The communication apparatus of feature (15), in which
the transmission request frame is a Poll frame.
(18) The communication apparatus of any one of features (1) to
(17), in which
the communication section exchanges capability information
regarding information synthesis using the original signal and the
retransmission signal with the sender of the retransmission
signal.
(19) The communication apparatus of any one of features (1) to
(18), in which
the communication section negotiates an MPDU (MAC Protocol Data
Unit) unit size in a MAC (Media Access Control) layer with the
sender of the retransmission signal.
(20) The communication apparatus of any one of features (1) to
(19), in which
the MPDU unit size in the MAC layer is an integer multiple of a
unit coding block in a physical layer.
(21) The communication apparatus of any one of features (1) to
(20), further including:
a synthesis section adapted to synthesize information by using the
original signal and the retransmission signal received by the
communication section.
(22) The communication apparatus of feature (21), in which
the synthesis section performs the synthesis on the basis of the
information regarding the configuration of the retransmission
signal.
(23) The communication apparatus of feature (22), further
including:
a retention section adapted to retain the original signal whose
demodulation has failed, in which
the synthesis section performs the synthesis by using the original
signal read out from the retention section and the retransmission
signal received by the communication section on the basis of the
information regarding the configuration of the retransmission
signal.
(24) The communication apparatus of feature (23), in which
the retention section retains bit strings acquired by demodulating
the original signal, and
the synthesis section performs the synthesis by using the bit
strings read out from the retention section and bit strings
acquired by demodulating the retransmission signal received by the
communication section on the basis of the information regarding the
configuration of the retransmission signal.
(25) The communication apparatus of feature (23) or (24), in
which
the retention section retains the original signal, and
the synthesis section performs the synthesis by using the original
signal read out from the retention section and the retransmission
signal received by the communication section, on the basis of the
information regarding the configuration of the retransmission
signal, at an intermediate stage of processing until conversion of
the signal received by the communication section into data.
(26) A communication method including:
by a communication apparatus
transmitting information regarding a configuration of a
retransmission signal for retransmitting information of an original
signal whose demodulation has failed to a sender of the
retransmission signal; and
receiving the retransmission signal transmitted from the sender on
the basis of the information regarding the configuration of the
retransmission signal transmitted.
(31) A communication apparatus including:
a communication section adapted to receive information regarding a
configuration of a retransmission signal for retransmitting
information of an original signal whose demodulation has failed,
generate the retransmission signal on the basis of the information
regarding the configuration of the retransmission signal received,
and transmit the generated retransmission signal to a sender of the
information regarding the configuration of the retransmission
signal.
(32) The communication apparatus of feature (31), in which
the information regarding the configuration of the retransmission
signal includes information regarding data whose retransmission is
requested.
(33) The communication apparatus of feature (32), in which
the information regarding the data whose retransmission is
requested includes information regarding an identifier of the data
and information regarding a length of the data.
(34) The communication apparatus of feature (33), in which
the information regarding the identifier of the data includes a
sequence number of an MPDU (MAC Protocol Data Unit) in a MAC (Media
Access Control) layer.
(35) The communication apparatus of feature (33) or (34), in
which
the information regarding the length of the data includes a byte
length of the MPDU (MAC Protocol Data Unit).
(36) The communication apparatus of any one of features (33) to
(35), in which
the information regarding the length of the data includes a block
count or a byte length of a coding block including, without excess
or deficiency, the MPDU (MAC Protocol Data Unit).
(37) The communication apparatus of any one of features (33) to
(36), in which
the information regarding the length of the data includes time of a
signal at an intermediate stage of processing until conversion of
the data into bit strings.
(38) The communication apparatus of any one of features (33) to
(37), in which
the information regarding the data whose retransmission is
requested further includes information regarding an order of the
data.
(39) The communication apparatus of feature (38), in which
the information regarding the order of the data includes
information regarding a connection order of the data.
(40) The communication apparatus of feature (38) or (39), in
which
the information regarding the order of the data includes
information regarding a rule indicating an order of the data and
new data.
(41) The communication apparatus of any one of features (32) to
(40), in which
the information regarding the configuration of the retransmission
signal further includes information regarding a setting of
information synthesis using the original signal and the
retransmission signal.
(42) The communication apparatus of feature (41), in which
the information regarding the synthesis setting includes a notice
to the effect that the synthesis will be performed.
(43) The communication apparatus of feature (41) or (42), in
which
the information regarding the synthesis setting includes an
identifier of a stream to be subjected to the synthesis.
(44) The communication apparatus of any one of features (41) to
(43), in which
the information regarding the synthesis setting includes
information regarding a scheme of the synthesis.
(45) The communication apparatus of any one of features (31) to
(44), in which
the communication section receives the information regarding the
configuration of the retransmission signal as part of a
transmission request frame of the retransmission signal.
(46) The communication apparatus of feature (45), in which
the transmission request frame is a Trigger frame.
(47) The communication apparatus of feature (45), in which
the transmission request frame is a Poll frame.
(48) The communication apparatus of any one of features (31) to
(47), in which
the communication section exchanges capability information
regarding information synthesis using the original signal and the
retransmission signal with the sender of the information regarding
the configuration of the retransmission signal.
(49) The communication apparatus of any one of features (31) to
(48), in which
the communication section negotiates an MPDU (MAC Protocol Data
Unit) unit size in a MAC (Media Access Control) layer with the
sender of the information regarding the configuration of the
retransmission signal.
(50) The communication apparatus of any one of features (31) to
(49), in which
the MPDU unit size in the MAC layer is an integer multiple of a
unit coding block in the physical layer.
(51) The communication apparatus of any one of features (31) to
(50), in which
in a case where retransmission of data that has already been
discarded is requested, the communication section notifies a
requester that the data has already been discarded.
(52) The communication apparatus of feature (51), in which
the communication section notifies the requester that the data has
already been discarded by transmitting Null data to the
requester.
(53) A communication method including:
by a communication apparatus
receiving information regarding a configuration of a retransmission
signal for retransmitting information of an original signal whose
demodulation has failed;
generating the retransmission signal on the basis of the
information regarding the configuration of the retransmission
signal received; and
transmitting the generated retransmission signal to a sender of the
information regarding the configuration of the retransmission
signal.
REFERENCE SIGNS LIST
100 Communication system, 101 Base station, 102 Terminal apparatus,
200 Communication apparatus, 201 Control section, 202 Data
processing section, 203 Wireless communication section, 211
Modulation/demodulation section, 212 Signal processing section, 213
Channel estimation section, 214 Wireless interface section, 215
Amplifier section, 216 Antenna, 221 Power supply section, 231
Demodulation section, 232 Signal retention section, 233 Signal
synthesis section, 900 Computer
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